Comparative studies on the temperature dependence of lactic and malic dehydrogenase from a homeotherm, guinea pig ( Cavia porcellus); two hibernators, hedgehog ( Erinaceus europaeus) and bat ( Nyctalus noctula); and two poikilotherms, from ( Rana temporaria) and cod ( Gadus callarias)

Abstract

1. 1. The temperature effects on V max and the isoenzyme distribution of LDH and MDH from tissue homogenates from guinea pig ( Cavia porcellus) hedgehog ( Erinaceus europaeus) (both hibernating and non-hibernating), bat ( Nyctalus noctula) (hibernating), frog Rana temporaria) and cod ( Gadus callaris) were examined. 2. 2. Correlations were found between the LDH-H activity and the energy of activation and inactivation of LDH. 3. 3. No correlation was found between the energy of activation of MDH and theMDH-isoenzyme distribution. 4. 4. No differences in the energy of activation of LDH or MDH were found between the animals. 5. 5. However, MDH from the mammals had higher temperature maxima than MDH from the poikilotherms.